Pluvial flood adaptation using nature-based solutions: An integrated biophysical-economic assessment

Area of Science:

• Environmental Science
• Urban Planning
• Climate Change Adaptation

Background:

• Flood events are the costliest natural hazard globally, exacerbated by urbanization and climate change.
• Coastal cities face increasing flood risks from sea-level rise, storm surges, and urban runoff.
• Nature-Based Solutions (NBS) are recognized for climate adaptation but their urban catchment-scale effectiveness requires empirical validation.

Purpose of the Study:

• To develop and apply a spatial biophysical-economic framework for assessing NBS flood risk mitigation.
• To integrate biophysical impacts, costs, and benefits of NBS under current and future climate conditions.
• To evaluate the effectiveness of green roofs and bioswales in a coastal city case study.

Main Methods:

• Utilized the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) Urban Flood Risk Mitigation model for biophysical impact assessment.
• Employed benefit transfer methods to evaluate the economic implications of NBS.
• Integrated biophysical and economic data using Geographic Information System (GIS) tools for spatial analysis.

Main Results:

• Green roof scenarios demonstrated an annual saving of 32% in flood damages to buildings and infrastructure.
• Bioswale scenarios showed a minimal saving of 0.1% in flood damages.
• Green roofs provided greater benefits in future climate scenarios (RCP 4.5).

Conclusions:

• NBS, particularly green roofs, offer significant potential for urban flood risk mitigation.
• The study highlights the partial and uncertain knowledge of NBS benefits and costs.
• Biophysical-economic assessments are crucial for informed, adaptive climate adaptation planning.